1. Field of the Invention
For the purposes of tilt adjustment (hereinafter referred to as "aiming") of an automobile head lamp, a lamp is provided with an aiming mechanism. Aiming is generally conducted by rotating an aiming screw which is inserted into a lamp body. The present invention relates to a push-on fixer for engaging the screw, which is used for preventing the aiming screw inserted into a lamp body of coming off of the lamp body.
2. Related Art
FIGS. 1 and 2 illustrate an aiming mechanism of a conventional automobile head lamp. FIG. 1 is a front view of the head lamp, and FIG. 2 is a vertical sectional view showing a profile (sectioned along the line II--II in FIG. 1) of the same head lamp. As shown in these drawings, a lamp body 1 and a front lens 2 define a lamp chamber space in which a reflector 3 is supported so as to be capable of being tilted by the aiming mechanism. A bulb 4 acting as a light source is installed in the reflector 3. The aiming mechanism consists of one pivot support 6a; a vertical aiming screw 6b which projects inside and outside lamp body 1, and is threadedly engaged with a reflector side nut (not illustrated) which is screwed onto this screw 6b; and a horizontal aiming screw 6c which similarly projects inside and outside the lamp body 1, and is threadedly engaged with a reflector side nut (not illustrated) which is screwed onto this screw 6c. By rotating the aiming screws 6b and 6c, the reflector 3 is tilted around the horizontal tilt axis L.sub.x and the vertical tilt axis L.sub.y, thereby aiming the head lamp.
FIG. 3 is a sectional view which shows an enlargement of the lamp body insertion portion of the aiming screws. The aiming screw 6b (6c) passes through a screw insertion hole 1a of the lamp body 1 so as to project to both the front and rear of the lamp body. The screw is prevented from coming off from the lamp body 1 by a push-on fixer 7 while it is rotatably supported in screw insertion hole 1a. As shown in an enlarged manner in FIG. 4, the push-on fixer 7 has a structure where a plurality of notches 7b are formed in a central circular hole portion of a thin discoid body 7a, thereby forming a plurality of plate spring pieces 7c in an inner circumferential edge. These plate spring pieces 7c clamp an engagement portion 6d of the aiming screw 6b (6c), whereby the aiming screw 6b (6c) is prevented from coming off of the lamp body 1. Reference numeral 8 designates a wave washer for eliminating any axial backlash in the aiming screw bearing portion; the reference numeral 9a designates an O ring for ensuring waterproofing in the aiming screw bearing portion; and the reference numeral 9b designates a sliding washer.
In the above-mentioned structure of the aiming screw bearing portion, the push-on fixer 7 and the wave washer 8 are indispensable. The number of parts is correspondingly large, and the time required for assembly is long.
Regarding installation of the push-on fixer, the push-on fixer can be easily installed because the screw 6b (6c) can be inserted into the circular hole while deforming the plate spring pieces 7c. However, once the push-on fixer is installed, its removal is difficult, and repair of the aiming screw bearing portion is inconvenient. In addition, there has recently been a tendency where the lighting fixtures removed from scrapped automobiles are disassembled, and the materials are sorted for recycling. Unfortunately, much labor is required to remove the push-on fixer 7 from the lamp body 1.